function s1_read_last_two_bytes_of_a_mbr_backup_file() {
	local file_path=$1
	local last_bytes=$(tail -c 2 "$file_path" | od -A n -t x1 | tr -d ' \n')
	if [ "$last_bytes" = "55aa" ];then
		echo "YES"
	else
	        echo "NO"
	fi
}

function s2_read_mbr_partition_table_info()
{
	echo -n $(echo "ibase=16; 800" | bc)
	echo -n ' '
	local mbr_backup_file=$1
	for i in {0..3}; do
	    local offset=$((446 + i * 16))
	    local partition_entry=$(od -j $offset -N 16 -t x1 -An "$mbr_backup_file" | tr -d ' \n')
	    local partition_type=$(echo $partition_entry | cut -c 9-10)
	    if [ "$partition_type" != "00" ]; then
		    local start_sector_hex=$(echo $partition_entry | cut -c 17-24 | tr '[:lower:]' '[:upper:]')
		    local start_sector=$(echo "ibase=16;$start_sector_hex" | bc)
		    local end_sector_hex=$(echo $partition_entry | cut -c 33-40 | tr '[:lower:]' '[:upper:]')
		    local end_sector_=$(echo "ibase=16;$end_sector_hex" | bc)
		    if [ $i -eq 0 ];then
			    echo -n "$end_sector "
			    echo -n "$start_sector "
		    else
			    echo -n "$end_sector"
	            fi
	        fi
	done
}


function s3_parse_partition_info()
{
	fdisk_output=$(cat)
	disk_size_bytes=$(echo "$fdisk_output" | grep "Disk /dev/vda:" | awk '{print $5}')
	disk_size_sectors=$(echo "$fdisk_output" | grep "Disk /dev/vda:" | awk '{print $7}')
	local physical_sector_size=$(echo "$fdisk_output" | grep -E "Sector size" | awk '{print $4}' | tr -d '()')
	first_partition_start_sector=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $3}')
        first_partition_end_sector=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $4}')
	first_partition_type=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $8}')
	echo "disk size in bytes:$disk_size_bytes"
	echo "disk size in sectors:$disk_size_sectors"
	echo "physical sector size in bytes:$physical_sector_size"
	echo "first partition start sector id:$first_partition_start_sector"
	echo "first partition end sector id:$first_partition_end_sector"
	echo "first partition type:$first_partition_type"
}

function s4_run_passwd_as_plain_user_and_get_status()
{
	oversleeping_path=$(which oversleeping)
	chown root "$oversleeping_path"
	chmod 755 "$oversleeping_path"
	$oversleeping_path &
	ps -o uid,euid,ruid -C 'oversleeping' | awk 'NR>1{print $1","$2","$3}'
}

function s5_add_a_scheduled_task()
{
	(crontab -l 2>/dev/null; echo "*/5 * * * * echo \$(date +'\%Y\%m\%d_\%H\%M\%S') >> \$HOME/test_crontab") | crontab -
}

